Question
A patient on lithium therapy developed hypertension. He was started on Thiazide for hypertension. After a few days, he developed coarse tremors and other symptoms suggestive of lithium toxicity. What is the probable mechanism of interaction?
A. Thiazide increases the tubular reabsorption of lithium
B. Thiazide inhibits the metabolism of lithium
C. Thiazides act as an add on the drug to lithium
D. All of the above
Show Answer
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Correct Answer » A
Explanation
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Ans: A. Thiazide increases the tubular absorption of lithium
Drug Interaction:
- Diuretics + Lithium = Decreased excretion—rise in Li + level – toxicity;
- Diuretics (thiazide, furosemide) by causing Na + loss to promote proximal tubular reabsorption of Na + as well as Li + → plasma levels of lithium rise. Potassium-sparing diuretics cause milder Li + retention.
- Management: Reduce dose of lithium and monitor level.
Ref: K. D. Tripathi 7th Edition. Page. 449, 932
